System for reducing power consumption of a wireless terminal and increasing capacity of a wireless communication system

ABSTRACT

A system and a method for reducing the power consumption of a wireless terminal and increasing capacity of a wireless communication system, without sacrificing the functions of the terminal. A base station includes a memory for storing the characteristics of the wireless terminal, the types of voice traffic that are supported by the terminal, and a program for executing an algorithm for exchanging control messages with the terminal via a wireless network. The algorithm is modified based on the particular characteristics of the wireless terminal, and sets the frequency of message exchange to not to exceed a predetermined frequency. In addition, the algorithm limits a time that information is displayed on the wireless terminal to a predetermined duration of time.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a system and a method for reducing thepower consumption of a wireless terminal and increasing capacity of awireless communication system without sacrificing functionality.

2. Description of Background Art

When a telephony terminal/endpoint is connected to a source (forexample, private branch exchange (PBX), router, private/public network,peer device) via wires or a cable, the source continuously updates theterminal with status and control messages, often at a frequency ofseveral hundred times per second. These messages are used to controlvisual, audible, and tactile display elements (some examples of theseelements might be alphanumeric displays, light emitting diodes (LEDs),ringers, icons).

However, conventional sources often do not have the capability todistinguish between different terminal types, including whether or notthe terminal is battery powered, in order to tailor the messages sentbased on individual terminal characteristics. When the terminal is wired(e.g.; connected through a dedicated line) and the terminal is poweredby the building power rather than a battery, handling of these messagescan be done continuously.

However, if the terminal/endpoint is battery powered and is connected bymeans of a wireless communications network, such continuous updates canunnecessarily prevent the endpoint/terminal from entering “low(er) powermode”. In fact, continuously updating by the source of certain messagesmay provide no benefit at all to the wireless terminal user. Forexample, if the time-of-day clock of a terminal is capable of onlydisplaying hours and minutes, no benefit results from having the sourcesend time-of-day updates messages at a rate of more than once/minute.

As mentioned above, many sources (switching platform/base stations) arenot equipped to determine whether or not that certain terminals havefinite power supplies (e.g.; battery powered). If the source of themessages is unaware that the terminal/endpoint has a finite powersource, there is no reason why these updates should not be continuous inorder to maintain timely and accurate information. However, unnecessaryupdates not only require greater terminal battery consumption, but theupdates also contend for finite bandwidth that exists over the wirelessmedium/channel, thereby reducing overall capacity for otherdevices/terminals/endpoints.

There are no known systems or methods to address these problems. Inorder to minimize the power consumption of a wireless terminal/endpoint,it would be desirable to have a way to limit the exchange of informationtransmitted from the base station to the wireless phone/terminal/endpoint. Further it would be desirable to limit the time that displayelements are displayed, in order to further limit battery drain andensure accurate information. In other words, in conventional systemsinformation may get stale over time; in this case displaying noinformation to the terminal is better than displaying stale or datedinformation.

SUMMARY AND OBJECTS OF THE INVENTION

The present invention was developed in order to address the problemsassociated with conventional wireless devices that are described above.The algorithm of the present invention runs under program control inconjunction with the base station or source, by determining that theterminal is battery powered, determining the characteristics of theterminal, and then customizing and limiting the exchange of informationtransmitted from the base station to the wireless terminal so that thebattery life of the terminal can be extended, while still maintainingthe features and capabilities offered by the source. The algorithmsucceeds in reducing the power consumption of the terminal withoutsacrificing features and/or capabilities that are provided by acommunications protocol that supports display elements. With the presentinvention, an algorithm running at a base station determines whether anupdate message should be transmitted to the wireless terminal/endpointbased upon the content of the particular display element of theterminal/endpoint, coupled with the call state of the terminal/endpoint.As shown in FIG. 1, the terminal/endpoint 10 communicates with basestation 20, and base station 20 is connected to the source 30, thesource being a public network, a private network, or a peer device forexample.

Further scope of applicability of the present invention will becomeapparent from the detailed description given hereinafter. However, itshould be understood that the detailed description and specificexamples, while indicating preferred embodiments of the invention, aregiven by way of illustration only, since various changes andmodifications within the spirit and scope of the invention will becomeapparent to those skilled in the art from this detailed description.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will become more fully understood from thedetailed description given hereinbelow and the accompanying drawingswhich are given by way of illustration only, and thus are not limitativeof the present invention, and wherein:

FIG. 1 shows a diagram of a base station connected to a source andcommunicating with a wireless terminal;

FIG. 2 shows examples of control messages and status indicatorsdisplayed on the wireless terminal;

FIG. 3 is a diagram showing the steps executed by the algorithm of thepresent invention when exchanging status and control messages with awireless terminal; and

FIG. 4 is a diagram showing the display clearing algorithm of thepresent invention.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

FIG. 1 shows a diagram of a base station 20 communicating with awireless terminal 10. The base station is connected to a source 30,which may include a public network, a private network, a peer device,etc. As can be seen the algorithm described herein resided in the basestation 20. By incorporating the algorithm into the base station 20, thebase station can analyze information coming from the source 30. Byconstantly analyzing the status and control information received fromthe source 30 coupled with the knowledge of the terminal/endpoint 10(the fact that it is wireless and it knows its current state), the basestation 20 can decide whether to pass the information on to theterminal/endpoint 10.

FIG. 2 shows examples of control messages displayed on the wirelessterminal. Here the sample terminal/endpoint contains an alphanumericdisplay screen D, a number of status indicators (visual indicatorsS1-S8), and display icons on the display screen D for indicating controlmessages. These display icons may show the information of an incomingcall, a text message showing an alarm on a server, and an illuminatedicon indicating an unread voice/email resides in the users mailbox, forexample.

Protocols used to supports telephony devices such as SIP (SessionInitiated Protocol), H.323, ISDN BRI (Basic Rate Interface), andproprietary protocols, transmit/receive control information oversignaling “channel” in order to control various display elements (i.e.,visual, audible, and tactile). One of the features provided in oneembodiment of the invention is the time-of-day clock. This is normallyupdated every minute on a wired terminal/endpoint. For wirelessimplementation described the invention, this display of the terminalshows only hours and minutes. In conventional systems prior to thisinvention, the display update capability of the system caused acontinuous radio transmission from the radio base station to theterminal. On the other hand, with the present invention, the algorithmenables the base station to tailor the updates and/or limit the updatesthat are sent based upon several variables of the system and theterminal, including the call state, and the display timer that describethe state of the call/phone.

The algorithm is detailed in FIG. 3. In particular, FIG. 3 (see StepsS10-S15) shows the steps of analyzing each type of message received fromthe source. An “image” of the terminal/endpoint is kept in memory toverify any state changes that the source may send either as an update orsimply as a “refresh”. In addition, the algorithm tracks other variablesthat describe the state of the terminal in order to see if status orcontrol information should be transmitted to the terminal/endpoint. Onesuch variable is the state of the voice connection. If a voice, orbearer “channel”, is currently established to the terminal then somemessages that would otherwise be “filtered” are now transmitted due tothe terminal, since it known to be already active.

Another feature provided by wireless communications protocols is theability to illuminate/extinguish visual indicators (LEDs) on theterminal 10. (See FIG. 2) This feature is shown with reference to StepsS20-S23 of FIG. 3. Visual indicators are used to convey status of voiceconnection, features and/or status indicators offered by the source. Theupdating and/or refreshing of these indicators is done a continuousbasis by the source in order to ensure that the information contained inthe terminal is up to date. The algorithm described herein stores thecurrent state of all visual indicators of terminal 10 in the memory ofthe base station 20. When an update comes from the source 30, the basestation 20 passes the information on to the wireless device 10 only ifthere is a change.

The communications protocol also enables display messages to be sent toterminal 10 in response to certain events such as the making/receiving acall, pressing a button, or conveying status information such as theaforementioned time and data. (See Steps S16-S19 of FIG. 3.) Thealgorithm only sends these display updates if the terminal/phone 10 isNOT in an idle mode. The idle mode is when there is no (voice) “bearer”channel and the terminal 10 and source 30 have successfully negotiatedthe “tearing down” of a voice call.

In conjunction with the items mentioned above, the invention alsoincludes the capability of limiting the time that terminal 10 displayscertain information. This is done to ensure that updates that are sentremain valid for only a fixed duration of time. A timer of the algorithmis set/reset based upon variables, such as those that are described inthe sections above. Prior to the present invention, the display updatesprovided would remain on the screen until a subsequent update from thesource occurred. Since the updates sent to the terminal by the algorithmof the present invention are intentionally less frequent, there needs tobe a way to ensure the updates do not get “stale”, thereby invalidatingthe accuracy of the information. The timer solves that issue, as well ascontributing to less power usage.

A display clearing algorithm is detailed in FIG. 4. In particular, FIG.4 shows the steps of clearing the display of time sensitive user datasuch as a timer of day (TOD) clock or timers that indicate the length ofa voice connection.

An advantage of the present invention is that the battery life of awireless device can be extended while still providing the value-addedfeatures that a source affords its wireless phone users.

In addition, the wireless terminal can exploit the value-added featuresoffered by the system, for example, multi-line function, callforwarding, conferencing, call holding, and others, while stillmaintaining the extended battery life that wireless device user'srequire. The algorithm of the present invention may be applied to anybase station implementation (for example, the source may be a privatebranch exchange (PBX), router, private/public network, peer device) andtelephony protocol (for example, SIP, H.323, ISDN BRI). The algorithmmay be implemented in the fixed-part/base station portion of the radiolink so it can be added to a system without modifying thesoftware/firmware of the phone/terminal, thus extending the useful lifeof the source (base station), and deferring or reducing upgrade costs.

The algorithm can be extended to any terminal connected to a switchingdevice, such as a wireless EP endpoint (802.11 for example). Theinvention can be applied to an 802.11 base station as a way of savingbattery life on an 802.11-based endpoint.

INDUSTRIAL APPLICABILITY

According to estimates by Telecompetition, Inc., global phone market isexpected to reach 2.2 billion subscribers by 2010, with 75% of theseusing some form of data. This figure does not include handsets for“private” networks, such as described herein. It is expected that in thefuture many “public” cellular phones will have provisions to operate ona “private” network, such as described herein.

The invention being thus described, it will be obvious that the same maybe varied in many ways. Such variations are not to be regarded as adeparture from the spirit and scope of the invention, and all suchmodifications as would be obvious to one skilled in the art are intendedto be included within the scope of the following claims.

1. A system for reducing power consumption of a wireless terminal,comprising: a base station having a program for running an algorithm forexchanging control messages with the wireless terminal via a wirelessnetwork, wherein a frequency for exchanging the control messages doesnot exceed a predetermined frequency.
 2. The system for reducing powerconsumption of a wireless terminal according to claim 1, furthercomprising an algorithm executed by a program in the base station forinitiating the exchange of the control messages.
 3. The system forreducing power consumption of a wireless terminal according to claim 1,wherein the control messages include signals for illuminating andextinguishing visual indicators, starting and stopping audible alerts,and presenting characters on a display screen of the wireless terminal,including updating a time of day.
 4. The system for reducing powerconsumption of a wireless terminal according to claim 3, wherein thecontrol message for updating the time-of-day is exchanged at 60 secondintervals.
 5. The system for reducing power consumption of a wirelessterminal according to claim 1, further comprising an algorithm executedby a program in the base station for initiating the exchange of statusmessages.
 6. The system for reducing power consumption of a wirelessterminal according to claim 5, wherein the status messages are exchangedonly when there is a change of status.
 7. The system for reducing powerconsumption of a wireless terminal according to claim 5, wherein thestatus messages convey status of lines, trunks, or calls.
 8. The systemfor reducing power consumption of a wireless terminal according to claim1, wherein the status messages are exchanged only when there is a changeof status and when the wireless terminal is not in an idle mode.
 9. Thesystem for reducing power consumption of a wireless terminal accordingto claim 1, wherein the base station is part of a private network. 10.The system for reducing power consumption of a wireless terminalaccording to claim 1, wherein the base station is part of a publicnetwork.
 11. The system for reducing power consumption of a wirelessterminal according to claim 1, wherein the base station is part of apeer-to-peer network.
 12. The system for reducing power consumption of awireless terminal according to claim 1, wherein the algorithm executedby a program in the base station limits a time that information isdisplayed on the wireless terminal to a predetermined duration of time.13. The system for reducing power consumption of a wireless terminalaccording to claim 1, further comprising a timer in the base stationadapted to be set and reset under operator control.
 14. A method forreducing power consumption of a wireless terminal, comprising the stepsof: executing an algorithm in a program of a base station forcontrolling the exchange of control messages with the wireless terminalvia a wireless network, wherein the algorithm limits a frequency forexchanging the control messages does exceed a predetermined maximumfrequency.
 15. The method for reducing power consumption of a wirelessterminal according to claim 14, wherein the control messages are usedfor display elements that include signals for illuminating andextinguishing visual indicators, starting and stopping audible alerts,and presenting characters on a display screen of the wireless terminal,including updating a time of day.
 16. The method for reducing powerconsumption of a wireless terminal according to claim 13, furthercomprising the steps of: determining the characteristics of theterminal; and modifying the execution of the algorithm based onparticular characteristics of the terminal.
 17. The method for reducingpower consumption of a wireless terminal according to claim 14, furthercomprising the step of: executing the algorithm the program in the basestation in order to exchange status messages only when a predeterminedcondition is met.
 18. The method for reducing power consumption of awireless terminal according to claim 17, wherein the predeterminedcondition is met only when there is a change of status.
 19. The methodfor reducing power consumption of a wireless terminal according to claim17, wherein the status messages convey status of lines, trunks, orcalls.
 19. The method for reducing power consumption of a wirelessterminal according to claim 16, wherein the predetermined condition ismet only when there is a change of status and when the wireless terminalis not in an idle mode.
 21. The method for reducing power consumption ofa wireless terminal according to claim 14, wherein the base station ispart of a private network.
 22. The method for reducing power consumptionof a wireless terminal according to claim 14, wherein the base stationis part of a public network.
 23. The method for reducing powerconsumption of a wireless terminal according to claim 14, wherein thebase station is part of a peer to peer network
 24. The method forreducing power consumption of a wireless terminal according to claim 16,further comprising the step of: determining types of voice traffic whichare supported by the terminal, having prior knowledge of the displayelements and time sensitivities of the terminal.